northeast-flora-and-fauna

Those of us living in the real world don't get a chance to see unicorns ... unless they are Unicorn Clubtail dragonflies, that is. But while the mythical unicorn has a very prominent horn, the Unicorn Clubtail has a more modest point on their occiput (an area between the eyes at the top of the head ). Although some descriptions call this point "conspicuous": It's pretty easy to miss it as a field mark, and isn't even easy to see in pictures like the 1 below. On the other hand, if you're an entomologist examining a captured dragonfly , it suddenly becomes a very useful way of identifying these guys. Clubtail dragonflies are a bit different from the average dragonfly:  Their abdomens are mostly thinner than other types of dragonflies, but which widen at the last few segments (S7-S9) into something like a club. At least this is usually true for the clubtails, though there are some species with virtually no club. (Unfortunately for the club analogy, the clubta...

While immature and sexually dimorphic species can look different (see Common Whitetails and Eastern Pondhawks ), sometime butterflies like the Mourning Cloak can present a different look just by repositioning its wings. (Other species that can do this include - but are not limited to - Red Admirals and Question Marks .) The 1st picture is their camouflage look, and while it doesn't blend in too well in this sandy soil, it can be quite a bit harder to spot them in leaf litter or against the bark of some trees. Though there's a light colored trim at the edges, they resemble something drab with a rough texture. June 15, 2023 at Sourland Mountain Preserve Photo 300991453, (c) jpviolette, some rights reserved (CC BY-NC) But then the butterfly opened its wings, allowing us a view of its rich brown wings with light spots highlighted by a black background and with almost a gold trim on the edges. And the wings that appeared to have a rough texture with the wings up suddenly seem to...

If you were wondering if the male Red-winged Blackbirds had any females around to impress, here's 1 of those female Red-winged Blackbirds . Sexual dimorphism is strong in these birds, sometimes fooling people into thinking the males and females are of different species. This particular bird seemed to be pretty busy under a stone bridge [1]. My 1st thought - this picture being from the spring - was that maybe she was building a nest under there. It would have the advantage of keeping her and her eggs out of the rain, and might be a location that aerial predators (hawks and owls) wouldn't find. And although they're not aquatic, Red-winged Blackbirds do like their lakefront properties. Thinking about it more though, I think this is unlikely. Red-winged Blackbirds don't generally gravitate towards man-made structures, and it seems unlikely there's enough vegetation under there for her to build a water-adjacent nest . Finally, I didn't see her bringing any material...

Last spring at the Plainsboro Preserve I noticed a couple of unusual "birds" at their bird feeders [1]. What was especially unusual about these birds was that their wings looked more like forelegs, and that their plumage had a furriness that you rarely see in adult birds [2]. I'm still struggling to ID them [3].

I read today that there is some sexual dimorphism among our Northern Red-bellied Cooters . Though in many of our turtles the females tend to be larger, in Northern Red-bellied Cooters the difference isn't great; a large male and a medium-sized female are probably going to be about the same size, and unless you see turtles pretty close up, judging subtle size differences can be error prone. But this article suggests that it's the females that have the distinctive reddish-orange plastrons while the plastrons of the males tends to be pinkish. And my field guide says that while the sides of the females look striped, the sides of the males look more mottled. That's why I'm suspicious that the 1st turtle below is a female and that the 2nd turtle picture is of a male (with a friend). Bright orange plastron + stripey side = Female March 16, 2023 at the Raritan Water Power Canal Photo 267710927, (c) jpviolette, some rights reserved (CC BY-NC) The presumed male Northern Red-bel...

For Mother's Day , here's a Canada Goose family I met last week at Lord Stirling Park. Technically I can't be sure the mother was in this picture - there was a 3rd adult Canada Goose that wasn't in the picture - but there's a 2/3 chance at least 1 of these was a mother goose [1]. My impression is that geese are considered to be pretty good parents. Compared to ducks, they tend to have smaller broods but devote more time and energy into raising them. And overall they seem to be doing a good job; our Canada Goose population has been rising steadily since the mid-60s [2]. May 12, 2023 at Lord Stirling Park [1] Finding a mother goose is also harder since Canada Geese are not sexually dimorphic ; males and females are phenotypically very similar, or sexually monomorphic. [2] They might be doing a little too well. Just the volume of their bodily waste probably has negative consequences in high population areas.

Here's an Eastern Tailed-Blue butterfly that's gray (aka grey ). Is this butterfly diseased? Is it a mutant ? With superpowers ? Does it have chameleon -like abilities? No, no, none we know about, and no. This is a female Eastern Tailed-Blue, and all of them are gray. For good or ill, we name many species based on their appearance even when sexual dimorphism occurs. This typically means we name a species after the appearance of the more eye-catching of the sexes, which (especially in birds) usually means they're named after the male. (It's possible that some misogyny also influenced this naming convention.) September 14, 2021 at Duke Farms Photo 168279967, (c) jpviolette, some rights reserved (CC BY-NC)

Sometimes members of the same species can look quite different, usually due to sexual dimorphism. For the female Eastern Tiger Swallowtail though, butterflies of the same sex can also look very different. Here is the dark morph of the Eastern Tiger Swallowtail. All dark morphs are females, and this morph is usually seen later in the season, August and onward. It actually has the underlying pattern that the yellow morph Eastern Tiger Swallowtails (see below) has, but instead of a black-on-yellow pattern the dark morph is more like a dark-black-on-light-black pattern. The dark morph is considered to be participating in Batesian mimicry , since they resemble the poisonous Pipevine Swallowtail . July 28, 2021 at Sourland Mountain Preserve Photo 148654982, (c) jpviolette, some rights reserved (CC BY-NC) I didn't see a yellow morph female Eastern Tiger Swallowtail on this trip, but the yellow morph female Eastern Tiger Swallowtail looks fairly similar to the males. They're yellow-an...

Let's show two of these guys today. They are a pair of Eastern Pondhawks I met about the same time a couple months back. The blue one is certainly a male. The green one is probably a female, though juvenile males of this species look an awful lot like females. As with many dragonflies, as the males age they become covered with pruinose, especially on the abdomen, but in Eastern Pondhawks you'll also see this on the thorax. In some species the pruinose is mostly white (like in Common Whitetails and Widow Skimmers), but in Eastern Pondhawks it's light blue. So while there's quite a bit of sexual dimorphism in mature Eastern Pondhawks, there's almost no sexual dimorphism amongst the juveniles. Finally, while it's possible that these 2 crazy kids might be a couple and have larvae together, it's at least possible the green one will eventually be a blue rival of the already-blue pondhawk. Presumed female Eastern Pondhawk June 17, 2021 at the Plainsboro Preserve P...

Here's a Zabulon Skipper I met at Negri-Nepote Native Grassland Preserve. This is a male; the females look a lot different. (There's that sexual dimorphism at work again.) While the males don't look much like the females, they do look quite similar to the Hobomok Skipper . The biggest difference is that the Hobomok would have darker veins going through those orangish patches. It's easy to think these butterflies are pretty close relatives. I meet these guys a lot. June 2, 2021 at Negri-Nepote Native Grassland Preserve Photo 136367674, (c) jpviolette, some rights reserved (CC BY-NC)

Here's a Red-winged Blackbird I met a couple months back. The astute observer will notice that isn't black and doesn't have red on the wings. This is the issue with identifying many female birds, especially when the species was named after the much-differently-feathered males, a form of sexual dimorphism .  These birds can be misinterpreted as European Starlings or sparrows or finches. I find it very helpful to see what male birds are around when I'm trying to identify the females since many times the males have more distinctive plumage.  Female Red-winged Blackbirds do have plenty of company in getting misidentified. Northern Cardinals, Indigo Buntings, and Baltimore Orioles are just a few species where the females look a lot different than the males. June 2, 2021 at Negri-Nepote Native Grassland Preserve Photo 136367750, (c) jpviolette, some rights reserved (CC BY-NC)

Staying with Wood Ducks , today I'm going to show a pair. Given the time of year, I'm suspicious that breeding is on their minds. They are another example of sexual dimorphism , where the males and females have basically the same size/shape but the plumage of the males is much different from that of the females. A novice could no doubt mistake them for different species. Seeing a prominent white eye ring is very suggestive that you're looking at a female Wood Duck. Apparently the males do have a more subdued plumage that kicks in as summer wanes. I don't think I've gotten a picture of one with that plumage though. March 31, 2021 at Duke Farms Same ducks, different view

Here's a female House Sparrow . Yesterday's male House Sparrows have more of contrast of colors; like with many passerines and ducks, the females have more subdued coloring (a form of sexual dimorphism ). In many cases the best way for me to figure out what female bird is out there is to see what species the males that are with them. This strategy isn't perfect: Sometimes there are "strays" that have none of their own species around, so they'll try and hang out with whoever has similar feeding habits. More rarely you'll correctly identify a pair of birds who end up breeding together ... but they're not the same species. (Mallards and American Black Ducks are just one example.) And of course sometimes you'll see no males around at all. Still, the old saying that "birds of a feather flock together" really does work most of the time. March 2021 at Finderne

Here's another Widow Skimmer I met. With no white on the wing or tail ( pruinose ), it's presumably a female. She is a member of the skimmer dragonfly family , considered to be the largest dragonfly family, though some members of the family have surnames like Whitetail, Pondhawk, Meadowhawk, etc. This family generally exhibits sexual dimorphism , frequently due to pruinosity.  Don't be confused by the picture. If that was a bee or butterfly, it's likely that we'd be witnessing a pollinator at work. But for the predatory Widow Skimmer, this is just a place to perch. July 14 at Duke Farms